Hi, i' studying Kotlin and want to make a simple web CRUD application for a book store. Can someone give me some resources to achieve this? I have little experience with web applications, i only did some simple servlets stuff before.

You should at least decide about the architecture of the web application you want to make. In Kotlin you can create both server-side web applications (targeting JVM) and client side web applications (targeting JS). Or even full-stack, multiplatform apps.

Full stack, i forgot to mention.

You can have a look at KVision (https://github.com/rjaros/kvision). In the https://github.com/rjaros/kvision-examples repository you will find a few example full-stack applications. I'm the creator of this framework, so I like to recommend it 😉